As a multimedia such as a broadcasting phone or a PMP phone has been built in a smartphone as a main function, the user can enjoy various contents through their smartphone. The demand for a wireless headset has also been increasing with these trends.
Among the wireless communication techniques, Bluetooth, which is a standard for wireless communication between wireless communication devices at a short distance with low power, serves to process data transmission between devices such as a computer, a smartphone, a headset, a personal digital assistant (PDA), a personal computer (PC), and a printer. Bluetooth is a communication technology that can transmit and receive data wirelessly, usually between 10 meters and maximally several hundred meters. A neckband-type speaker for reproducing sound, with being worn around the wearer's neck, without a separate communication cable, has been developed using such a technology and sold on the market.
In addition, the sound generated by the conventional neckband-type speaker is transmitted not only to the wearer but also to the surroundings of the wearer, which disturbs the wearer listening to the sound and unwantedly transfers the sound to the people around the wearer.